Hi,
I know ithere are many threads with regards to roof insulation but one thing i cant get the hang of is this moisture thing. I have a 1930s house with a slate roof, and no felt lining, aparently its the way it was done this. my loft space is drafty with lots of gaps at either end, i dont think there is ventilation at the eaves but there is some slots at the ridges. I bought plenty of insulation and plenty of celotex 50mm boards. I had a roofer come and see the loft and roof and said it was bone dry and just needed 3 slates replacing. as for insulation he said to put in kingspan. now the issues i have is about the gap between the insulation board and the slate (as i have no felt).. my joists are only 7.5 cm thick and the boards are 5cm thick which leaves 2.5cm haha... i read you need 5cm gap... i also read it only applies to roofs with felt and hence as i have not got any does that mean i can flush fit my boards or even fit with only 2.5 cm gap. im worried about ventilation as i am in the process of foaming any gaps at the sides of the roof where the brick foundations are. any tips?
I know ithere are many threads with regards to roof insulation but one thing i cant get the hang of is this moisture thing. I have a 1930s house with a slate roof, and no felt lining, aparently its the way it was done this. my loft space is drafty with lots of gaps at either end, i dont think there is ventilation at the eaves but there is some slots at the ridges. I bought plenty of insulation and plenty of celotex 50mm boards. I had a roofer come and see the loft and roof and said it was bone dry and just needed 3 slates replacing. as for insulation he said to put in kingspan. now the issues i have is about the gap between the insulation board and the slate (as i have no felt).. my joists are only 7.5 cm thick and the boards are 5cm thick which leaves 2.5cm haha... i read you need 5cm gap... i also read it only applies to roofs with felt and hence as i have not got any does that mean i can flush fit my boards or even fit with only 2.5 cm gap. im worried about ventilation as i am in the process of foaming any gaps at the sides of the roof where the brick foundations are. any tips?